Many speakers, such as speaker modules, produce sound waves by vibrating an acoustic membrane. For example, electromagnetic speakers generate magnetic flux utilizing center and side magnets. Such magnetic flux moves a voice coil that is coupled to an acoustic membrane, thus vibrating the acoustic membrane and producing sound waves.
However, such speakers may not function correctly if movement of the acoustic membrane is hindered. For example, liquid or other substances may enter the speaker and hinder movement of the acoustic membrane.
Further, such movement may be hindered by differences in barometric pressure. If the difference between the barometric pressure on an external side of the acoustic membrane and the barometric pressure on an internal side of the acoustic membrane is too great, the acoustic membrane may be deformed and/or may not be able to expand in order to vibrate appropriately.
Regardless, if movement of the acoustic membrane is hindered, the speaker may not be able to produce sound waves as intended. This may result in distorted sound output. Such distortion may continue until the barometric pressure on the external side of the acoustic membrane is equalized with the barometric pressure on the internal side of the acoustic membrane.
Similarly, many microphones or microphone modules, detect sound waves by monitoring output of a voice coil coupled to an acoustic membrane that is vibrated by sound waves. Hindering of the acoustic membrane of such a microphone may cause distortion in the detected sound waves for similar reasons to those already discussed.